textproduct: Albany

UPDATE

As of 625 AM EST...Broken band of lake effect snow is still ongoing off Lake Ontario. MRMS shows on and off light snow showers still extending across the western Mohawk Valley and into parts of Schoharie County, the Albany Hill Towns and the eastern Catskills and mid Hudson Valley of Greene County. Radar imagery and NYS mesonet webcams show most of this activity is fairly light and additional accumulation this morning will be limited to just a fresh coating. With high pressure building towards the area, inversion heights will be lowering. CAMs suggest this band will diminish greatly towards 9 or 10 AM and will be retract closer to the lakeshore. Have adjusted temps to account for the ongoing snow showers and clouds with the lake band with morning temps starting out in the mid 20s to lower 30s.

SYNOPSIS

Lake effect snow showers will diminish this morning, allowing for a partly sunny and brisk Saturday. Clouds will increase this evening, with a mix of light rain and snow impacting the region for late tonight into Sunday with moderate snow totals expected for the western Adirondacks. After a brief break on Monday, another storm system will bring a more widespread accumulating snowfall to the region for Tuesday.

SHORT TERM /THROUGH MONDAY NIGHT/

Key Message:

- Winter Weather Advisory issued for western Adirondacks for late tonight into Sunday due NBM probabilities showing a 50%-70% chance for 4+ inches across northern Herkimer and Hamilton Counties

Discussion:

As of 117 AM EST...The large upper level trough that has been impacting the region is starting to push off to the east across New England. In the wake of the departing trough, the flow aloft has continued to shift and is now more northwesterly. The band of lake-effect snow off Lake Ontario has continued to shift southward and is now primarily impacting the northern and eastern Catskills, including southern Schoharie, Greene and northern Ulster Counties. Some snow showers and flurries are even making into the mid Hudson Valley and parts of the Taconics as well. Radar imagery shows the band is fragmented and not steady snowfall, but periods of light to moderate bursts could allow for additional accumulation of a coating to an inch or so over the next few hours. CAMs suggest that this lake effect will beginning weakening towards daybreak into the morning on Saturday and should be retracting closer to the lakeshore. Model soundings shows inversion heights falling through the day on Saturday, so the main threat for any lake effect across our area will generally be through sunrise, as the bulk of any additional activity during the day on Saturday will be mainly confined to areas across central New York.

After sunrise, some lingering lake clouds are expected for high terrain areas, but some breaks are expected for the valley areas. There should be improvement in sky cover through the day and skies will be partly to mostly sunny by afternoon on Saturday as high pressure builds over the area. With temps aloft still chilly, most areas will continue to see highs only in the 30s. While not as windy as the past few days, it will still be a little breezy at times, with some gusts reaching 20 mph.

The next storm system will be quickly heading across the Great Lakes for tonight. Clouds will be quickly increasing this evening, with skies becoming overcast for tonight. Lows will bottom out by the late evening in teens and 20s, but temps will either hold steady or slowly rise for the late night hours thanks to the increased clouds and a developing south to southwest flow at low levels.

With the warm advection increasing, periods of light precip will develop for the late night hours and into the morning on Sunday. With this type of setup, there may be little or limited precip across southern areas, but some enhancement is expected across the Adirondacks, where the southerly flow will upslope the terrain. For all areas, precip may begin as snow, but it will transition to rain across most of the area outside of the Adirondacks and southern Greens. Most of the region will see just a coating to an inch of snowfall, although the Adirondacks will see a moderate accumulation, thanks to the upslope flow producing more precip and temps staying cold enough for frozen precip. Have gone with a Winter Weather Advisory for N. Herkimer and Hamilton Counties, where a widespread 4 to 8 inches of snowfall is anticipated from this system. Most of the precip will be through the early afternoon hours thanks to the warm advection/isentropic lift. However, some additional precip (rain for most of the region) is expected ahead of the storm's cold front for Sunday afternoon into Sunday evening. Most areas will see precip done by 7pm Sunday or so, although some lingering upslope or lake-enhanced snow showers may continue into the western Adirondacks for Sunday night. Temps will reach the lower 40s for valley areas on Sunday, although high terrain areas will stay in the 30s. In addition, the strong pressure gradient will keep southerly winds gusty ahead of the cold front on Sunday, with some gusts up to 30 mph.

Aside from some early in the day snow showers over the western Adirondacks, high pressure should allow for dry and quiet weather for Monday into Monday night. It will be partly to mostly sunny on Monday with highs in the mid 20s to upper 30s. Some clouds may increase by late Monday night, otherwise it will dry and cold with lows in the teens and 20s.

LONG TERM /TUESDAY THROUGH FRIDAY/

Key Message:

- Southern stream low pressure system passing from the Northeast coast will bring a widespread accumulating snowfall to the region for Tuesday into Tuesday Night. Latest NBM probabilities show a 30-60% chance for 4+" across the forecast area, with the greatest probabilities across the Catskills, Capital Region, southern Vermont and Berkshires.

Discussion:

An impactful winter storm is anticipated to start the long term period. While there is good confidence that a storm will be tracking close to the Northeast coast for Tuesday into Tuesday night, there still remains questions regarding the exact storm track and QPF amounts.

A southern stream low pressure area will be lifting from the Deep South towards the Southeast coast, where an additional area of low pressure will reform near the mid Atlantic coast for Tuesday afternoon and lift northeast towards the New England coast for Tuesday night. Models have been different regarding how close to the coast the storm tracks, the strength of the low pressure area, and how far north the precip shield will be.

We are fairly confident that temps (both at the surface and aloft) will be fairly cold over most of the area, allowing for any precip to be in the form of snow. The exception may be far southern mid Hudson Valley and NW CT, where some rain could mix in if the storm track is further north. With the differing model solutions, we have closely followed the model blend. Latest NBM shows 30-60% of 4+", with the highest values in the Catskills, Capital Region, southern VT and Berkshires. Models have hinted at a strong gradient on the northern side of the storm, and this is especially seen in the solutions showing a strong (sub-990 mb) low off the coast. This widespread snowfall will likely have an impact on the Tuesday evening commute and may be the first widespread accumulating snowfall for the bulk of the region. Some solutions have shown as heavy accumulation at times. NBM probabilities remain in the 15-30% range for 10+", which is fairly noteworthy given this is still 4+ days out. While it's not a guarantee for widespread heavy snowfall, it's certainly a high enough percentage to continue to closely watch model trends. Guidance seems to suggest the storm will wind down on Tuesday night, with dry weather returning by Wednesday morning.

Behind this storm system, temps appear to remain below normal for the mid to late week, with highs only in the 20s and 30s, and overnight lows in the teens (with even some single digits by the late week). At this point, no additional impactful systems are anticipated for the late week.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Through 12z/Sun..Lake effect snow showers continue to impressively hang on this morning with some showers still extending well inland just south of KALB. They should remain south and west this morning, but in the event something does get nearby, included VCSH until 14z/Sat. As high pressure builds in today, these lake effect showers should diminish further this morning. Otherwise, VFR conditions are expected at all sites today into the overnight hours with mixed VFR/MVFR cigs continuing at KPSF through about 14-15z/Sat. Clouds will thicken and lower overnight as another low pressure system arrives. Some warm advection light snow showers could clip KALB/KPSF/KGFL after 08z/Sun and included a PROB30 for this potential. Cigs could lower to MVFR for some sites after 08z/Sun with bases lowering to 2000-3000 feet. Westerly winds between 10-15 kt with gusts 20-25 kt are expected into this afternoon before trending light to calm this evening. Overnight, winds will either remain calm or become southeasterly at around 5 kt (mainly KALB/KPSF).

Outlook...

Sunday Night: Low Operational Impact. Breezy. Slight Chance of RA. Monday: Low Operational Impact. Breezy. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: High Operational Impact. Definite SN. Tuesday Night: Moderate Operational Impact. Chance of SN. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: Low Operational Impact. NO SIG WX. Thursday: Low Operational Impact. Breezy. Slight Chance of SN.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Winter Weather Advisory from 1 AM Sunday to 1 AM EST Monday for NYZ032-033. MA...None. VT...None.